Registration Dossier
Registration Dossier
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EC number: 204-385-8 | CAS number: 120-32-1
Dissociation constant
Administrative data
Link to relevant study record(s)
- Endpoint:
- dissociation constant
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 16 Nov 2001 to 4 Oct 2002
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- EPA OPPTS 830.7370 (Dissociation constants in water)
- Deviations:
- not specified
- GLP compliance:
- not specified
- Dissociating properties:
- yes
- No.:
- #1
- pKa:
- 9.59
- Temp.:
- 25 °C
Reference
pKa Value - Results
Titration data sets of pH against volume of titrant were manipulated electronically using pKaLOGP v5.1. Six apparent pKa values in the presence of co-solvent were evaluated. Using the same software a “Multi-set” of the six data sets was formed and a Yasuda-Shedlovsky extrapolation performed to calculate the pKa value at zero percent organic content. Two of the six points were excluded from the Yasuda- Shedlovsky plot due to their poor fit with the line. The pKa was evaluated to be 9.59.
Description of key information
pKa is 9.59 at 25 ºC (OPPTS 830.7370).
Key value for chemical safety assessment
Additional information
Due to low water solubility of the test substance the titrations were performed using varying amounts of co-solvent methanol. The result was calculated by extrapolation to zero-organic content using the Yasuda-Shedlovsky theorem.
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